Lubricant and the method of preparing the same



Fatented May 16, 1944 PATENT OFF LUBRICANT AND THE 'METHOD OF PREPARING THE SAME Reuben A. Swenson, Hammond, Ind., assignor to Standard Oil Company, Chicago, 111., a corporation of Indiana No Drawingg 16 Claims.

The present invention relates to improvements in lubricants and more particularly to improved greases adapted for use under conditions of high temperature and pressures and the method of preparing the improved greases.

The compositions of the present invention are particularly well suited as lubricants such as mill greases, gear shield lubricants and other similar lubricants capable of providing adequate lubrication under extreme pressure and temperature conditions.

An object of the present invention is to provide a lubricant resistant to high temperatures and pressures. Another object of the invention is to provide a lubricant resistant to hot water. Still another object of the invention is to provide a smooth, stringy and tacky lubricant having sufficient fiber structure to adhere tenaciously to open gears. A further object of the invention is to provide an improved method of preparing such lubricants. Other objects and advantages of the invention will become apparent as the description thereof proceeds.

I have discovered that the foregoing objects can be attained by employing a lubricant containing in its broadest aspect a complex lead soap and solubilizers of the type hereinafter described. The lubricant can contain carbon black permanently dispersed or suspended therein.

The soap base of my improved lubricant is a complex soap of lead and an alkali metal or an alkaline earth metal. In my copending application, Serial No. 326,785, filed March 29, 1940, now Patent No. 2,295,189, granted September 8, 1942, of which the present application is a continuation-impart, there are described lubricants containing a new and novel'complex lead soap of lead and a metal of the alkali group or a metal of the alkaline earth group, prepared according to the following equation.

I have now discovered that improved greases of the foregoing type are obtained by incorporating therein a glycero'xide of a metal selected from the group consisting of alkali metals and alkaline earth metals, for example, sodium glyceroxide,

Application July 31, 1941, erial No. 404,895

potassium glyceroxide, calcium glyceroxide and the like. The metal constituent of the glyceroxide may correspond with the metal constituent of the metal-lead soap or it may be a different metal.

A lubricant containing a metal glyceroxide can be obtained by modifying the procedure described in my copending application for preparing the complex lead soap base of the above type. In accordance with the present invention, twice as much alkali as is normally required for the fat saponiflcation as indicated by the above equation is used. By employing this amount of excess alkali there is obtained in addition to the complex lead soap, a metal glyceroxide. The following reaction illustrating the action of an hydroxide of an univalent metal on a fat in the presence of an oxide of lead is believed to take place.

in which M is a metal selected from the group consisting of alkali metals and alkaline earth metals such as, for example, calcium, barium, strontium, potassium and preferably sodium. The metal glyceroxide obtained in accordance with the above formula contributes to the improved properties obtained since it functions as a solubilizing agent and imparts a degree of stringiness to the lubricant which is highly desired.

The fatty material employed in the preparation of the complex soap can be any fat or fatty oil, particularly those containing fatty acids having eight or more carbon atoms, or mixtures of such fatty materials. Examples of fatty materials which can be employed are animal fats and fatty oils, such as, for example tallow, beta fat, etc., fish oils, for example menhaden oil, and others.

In addition to the complex lead soap and the metal glyceroxide the improved lubricants of the present invention contain also a second solubilizing agent, mineral oil, and if desired, a filler, such as carbon black.

The second solubilizing agent'employed in accordance with the present invention is a metal soap of preferentially oil-soluble sulfonic acids or naphthenic acids, preferably those obtained in the treatment of petroleum oils with concentrated sulfuric acid. The preferentially oil-soluble sulfonates are well known in the art and are commonly referred to as mahogany soaps because of their characteristic mahogany color. These soaps usually contain approximately 40% metallic sulfonates, 40% unsulfonated petroleum oil and 20% of water and sulfates. They will be referred to hereinafter and in the appended claims as mahogany soaps. Although I prefer to use the sodium mahogany soap, other metallic soaps of mahogany acids such as potassium, calcium, barium, aluminum, iron and lead soaps can be used.

While preferentially oil-soluble sulfonates derived from petroleum oils in general can be employed, I prefer to use the metal derivatives of preferentially oil-soluble sulfonates obtained by treating distillatcs of 200-400 seconds Saybolt Universal viscosity at 100 F. with from about 7 to about 8 pounds of fuming sulfuric acid per gallon of oil.

If desired the filler, such as for example, carbon black may be omitted. However, since carbon black is effective in increasing the water resistance and also improving the heat resistance of the lubricant its presence is advantageous.

The mineral oil constituent of the lubricant can be, depending upon the particular use, any lubricating oil, preferably a mineral lubricating oil ranging in Saybolt Universal viscosity at 100 F. of from about 80 seconds to about 10,000 seconds or higher. of fractions of oils of various viscosities to give the desired viscosity, or it may be a single fraction. Also, the oil may be distillate oil or residual oil or blends thereof.

The amount of the complex lead soap, for example, soda lead soap, which may be used in the lubricant can vary from about 1% to about 50% or more Lubricants having these maximum and minimum soap contents may, for example, contain the following approximate compositions, the amounts being on a weight percentage basis.

Per cent Complex lead soap 1.0 to 50.0 Metal glyceroxide 0.1 to 6.0 solubilizer 0.05 to 15.0 Oil 97.85 to 9.0

Filler (e. g. carbon black) 1.0 to 20.0

Ingredient 1% soap 60% soap Pounds Pounds Tallow 0. 57 4 Sodium mahogany soap (water free basis). 0.06 14. 2 Dry caustic soda 0. l6 7. 8 Litharge 0. 46 22. 8 Carbon black l. 20. 0 Petroleum oil 07. 70 8. 0

In preparing the lubricant all of the tallow and the sodium mahogany soap, and from about 10% to about 20% of the petroleum oil are charged into a mixer. All of the carbon black, if used, is then added and the contents of the mixer stirred until the base is smooth. Then from about %to about additional petro- Further, the oil may be a blend leum oil is added, and the contents of the mixer heated to a temperature of from about F. to about F. All of the caustic soda is then added, preferably in a 48 Baum solution, at a temperature of about 160 F. and the batch maintained at about 180 F. to 200 1''. until the base becomes thickened. All of the litharge is then added and the temperature raised slowly to about 500 F. and held within the range of 500 to 520 F. until the mixture is smooth. At this time the balance of the petroleum oil is added and the batch allowed to cool to a temperature of from about 300 F. to about 330 F. during the grading in process. As soon as the batch is uniform it is put into containers. Inpreparing lubricants or various consistencies, it is advantageous to first prepare a lubricant of the desired maximum soap content and then prepare softer grades by grading in the necessary additional petroleum oil.

The following formulae show the approximate proportions of ingredients employed in preparing three grades of a. lubricant made in accordance with the present invention. The heavy and medium grade lubricants are suitable as gear shield lubricants andthe' softer grade lubricant is a viscous semi-fluid lubricant adapted to lubricate cables, journals and roll necks operating at elevated temperatures;-

1 Baybolt Universal viscosity at no r. 5.000 seconds.

Lubricants prepared from the above formulae will have the following compositions on a weight percentage basis Heavy Medium sen Per cent Per cent Per cent mo 11.; 4.2 1.8 1.3 0. s as 1.9 0.1 0.0 4.5 1.1 a s a s 0. 2 14.: 80.5 92.7

I Saybolt Universal Viscosity at 100 F. 5,01!) seconds.

Greases of the foregoing type are smooth, stringy. and tacky but still suiiiciently fibrous to be pulled back to the face of the gear teeth after each revolution, do not lose consistency on working, and are highly resistant to hot water. The latter property is essential in the lubrication of many journals and roll necks which are water cooled,

While the present invention has been described and illustrated with respect to certain embodiments thereof, the same are not to be construed as limiting the scope of the invention, except insofar as included in the accompanying claims.

I claim:

1. A lubricant containing a complex soap of lead and a metal selected from the group consisting of alkali metals and alkaline earth metals, 8. glyceroxide of a metal selected from the group consisting of alkali metals and alkaline earth metals, a solubilizer selected from the group consisting of a metal soap of preferentially oil-soluble sulfonic acid and a metal soap of preferentially oihsoluble naphthenic acid and mineral oil.

13. A method of preparing a heat resistant and 2..A lubricant containing a complex soap of lead and a metal selected from the group consisting of alkali metals and alkaline earth metals, a glyceroxide of said metal, a solubilizer selected from the group consisting of a metal soap of preferentially oil-soluble sulfonic acid and a metal soap oi preferentially oil-soluble naphthenic acid, and mineral oil.

3. A lubricant as described in claim 2 in which the metal glyceroxide is sodium glyceroxide,

4. A lubricant as described in claim 2 in which the metal glyceroxide is potassium glyceroxide.

5. A lubricant as described in claim 2 in which the metal glyceroxide is calcium glyceroxide,

6. A lubricant as described in claim 2 in which the solubilizer is sodium mahogany soap.

'7. A lubricant containing a complex soap of lead and a metal selected from the group consisting of alkali metals and alkaline earth metals, a glyceroxide of said metal, a soap of preferentially oil-soluble petroleum sulfonic acids, mineral oil and carbon black.

8. A lubricant containing sodium lead soap of a fatty material containing fatty acids having more than eight carbon atoms in the molecule,

sodium glyceroxide, sodium mahogany soap, petroleum lubricating oil, and carbon black 9. A lubricant comprising the following approximate composition:

Per cent by weight Complex lead soap 1 to 50 Metal glyceroxide 0.1 to 6 Sodium mahogany soap 0.05 to Mineral oil 97.85 to 9 Filler 1 to Per cent by weight Complex lead soap 1.0 to 50.0 Metal glyceroxide 0.1 to 6.0 sodium mahogany soap 0.05 to 15.0 Carbon black 1.0 to 20.0 Free litharge and alkali 0.02 to 1.2 Mineral oil 97.83 to 7.8

water resistant lubricant containing the following ingredients:

Sodium mahogany soa comprising the steps, mixing all of the tallow. the sodium mahogany soap and the carbon black with a portion of the petroleum oil until the base is smooth; heating the mixture to a temperature of from about 160 F. to about 180 F. and adding all of the caustic soda in a 48 Baum solution; stirring the mixture at a temperature of from 180 F. to about 200 F. until the base becomes thickened; adding all of the litharge to the mixture, and increasing the temperature to about 500 F. to 520 F.; stirring the mixture at the last named temperature until the mixture is smooth, and subsequently grading in the additional petroleum oil at a temperature of from about 300 F.

' to about 330 F.

14. A method of preparing a heat resistant and water resistant lubricant containing the following ingredients:

Tallow Sodium mahogany soap Dry caustic soda Petroleum oil Litharge comprising the steps, mixing all of the tallow and the sodium mahogany soap with a portion of the petroleum oil until the base is smooth; heating the same to a temperature of from about 160 F. to about 180 F. and adding all of the caustic soda in a 48 Baum solution; stirring the mixture at a temperature of from 180 F. to about 200 F.

said complex lead soap being the soap 0! lead and i a metal selected from the group consisting of alkali metals and alkaline earth metals and said metal glyceroxide being the glyceroxide of a metal selected from the group consisting of alkali metals and alkaline earth metals.

11. A lubricant containing the following approximate composition:

1 Per cent by weight Sodium lead tallow soap 1.0 to 50.0 Sodium glyceroxide 0.1 to 6.0 Sodium mahogany soap 0.05 to 15.0 Carbon black 1.0 to 20.0 Mineral oil 97.85 to 9.0

12. A lubricant containing the following approximate compositio Litharge and tree sodium hydroxide- Oil (ill until the base becomes thickened; adding all of the litharge to the mixture and increasing the temperature to about 500 F. to 520 F.; stirring the mixture at the last named temperature until the mixture is smooth, and subsequently grading in the additional petroleum oil at a temperature of from about 300 F. to about 330 F.

15. A method of preparing a heat resistant and water resistant lubricant containing the following ingredients:

Fatty material Dry caustic Litharge Preferentially oil-soluble metal sulfonate Petroleum oil mixture is smooth and subsequently grading in,

the additional petroleum oil at a'temperature oi from about 300 F. to about 330 F.

16. A lubricant containing a complex soap of lead and a metal selected from the group consisting of alkali metals and alkaline earth metals, 8. glyceroxide of a metal selected from the group consisting of alkali metals and alkaline earth metals, and mineral oil.

REUBEN A. swENsoN. 

